Power tong



Nov.vl8, 1952 c, LUNDEEN POWER TONG 7 Sheets-Sheet 2 Filed Dec. 50. 1947 C. A. LUNDEEN POWER TONG Nov. 18, 1952 7 Sheets-Sheet 3 Filed Dec. 30, 1947 INVENTOR. 6/ /55 7-5? ,4 Z u/vazzw,

fiTTO/WE'VEO Nov. 18, 1952 c. A. LUNDEEN POWER TONG 7 Sheets-Sheet 4 Filed Dec. 50. 1947 INVENTOR. flfissrse 4 4 0/1/0155,

Nov. 18, 1952 c. A. LUNDEEN POWER TONG 7 Sheets-Sheet 6 Filed Dec. 50. 1947 m m Mm QM. m M M mm Q Q m $N MW M 5% NZ W MN m A QM m H r .3 5 w W mm NM NM m6 wm mw N\\ $u N \N m Nov. 18, 1952 C. A. LUNDEEN I POWER TONG 7 Sheets-Sheet 7 Filed Dec. 50, 1947 JNVENTOR. 6 195.575,? 4. A u/vaflw BY v Patented Nov. 18, 1952 POWER TONG Chester A. Lundeen, Los Angeles, Calif., assignor to Byron Jackson 00., Vernon, Calif., a corporation of Delaware Application December 30, 1947, Serial No. 794,745

18 Claims.

This invention relates to power driven tongs of the type used for screwing or unscrewing threaded sections of pipe. This invention is particularly useful in connection with joining or unjoining sections of tubing, drill pipe, or casing as employed in drilling a well or producing fluid therefrom.

The principal object of this invention is to provide a novel form of power driven pipe tong.

Another object is to provide a tong device having an integral ring rotatably mounted and provided with a radial pipe opening, and having a novel form of pipe gripping device carried by the ring.

Another object is to provide such a tong device in which a jaw carrier is mounted on a power driven ring, and gripping jaws on the carrier are arranged to grip the pipe upon relative co-axial rotary movement of the carrier and ring.

Another object is to provide a power driven pipe tong having a frame provided with a pipe entrance slot, an integral power driven ring rotatable on the frame and provided with a similar slot, together with novel means for aligning said slots.

A more detailed object is to provide a new and improved form of guard adapted to provide a barrier across the entrance slot in the frame.

A further object is to provide detailed improvements in the manner of supporting and driving the rotatable ring. 1

Other objects and advantages will appear hereinafter.

In the drawings:

Figure 1 is a top plan view showing a preferred embodiment of my invention, the air motor being omitted.

Figure 2 is a side elevation thereof.

Figure 3 is a top plan view on an enlarged scale and partly broken away, as shown substantially on the lines III-III in Figure 2.

Figure 4 is a front elevation.

Figure 5 is a sectional detail showing the movable pipe-gripping jaw in its retracted position.

Figure 6 is a view similar to Figure 5 and showing the movable pipe-gripping jaw in its operative position.

Figure '7 is a transverse sectional elevation of the supporting ring and its associated parts taken substantially on the lines VIIVII as shown in Figure 5.

Figure 8 is a perspective exploded view showing the ring carrier and associated parts.

Figure 9 is a perspective view of the guard employed in connection with my device.

Figure 10 is a sectional elevation taken substantially on the lines X-X as shown in Figure 1.

Figure 11 is a sectional detail taken substantially on the lines XI-XI as shown in Figure 1.

Figure 12 is a sectional view taken substantially on the lines XII-XII as shown in Figure 1.

Figure 13 is a partial sectional elevation taken substantially on the line XI1IXIII as shown in Figure 6.

Figure 14 is a sectional view taken substantially on the line X[VXIV as shown in Figure 3.

Figure 15 is a sectional view of the positioning valve, shown in closed position and taken substantially on the lines XV-XV as shown in Figure 2.

Figure 16 is a .view similar to Figure 15 with the positioning valve shown in open position.

Figure 17 is a diagrammatical view of the piping connecting the positioning valve and air motor.

Figure 18 is a view similar to Figure 6 but illustrating the fixed and movable jaws in position to rotate the pipe in a counterclockwise direction.

Referring to the drawings, the tong device it! is provided with a frame generally designated ll. The frame ll includes a base 12 and a detachable cover l3 connected to the base by means of a plurality of releasable bolts la. The base [2 and cover 13 cooperate to provide an inclosure [5. Within this inclosure is positioned an integral ring "5 having a side entrance opening ll defined by the parallel walls I8 and IS. The ring [6 is rotatably supported on the frame II by means of a plurality of grooved rollers 23 which engage the surfaces 2i provided on the ring IS. A sufficiently large number of rollers 20 is provided to support the ring 16 adequately regardless of the position of the side opening Thus, as shown in Figure 3 of the drawings, six rollers 20 are mounted on the frame II and are carried on upwardly extending shafts 22, 23, 24, 25, 26 and 21. Shafts 22 and 21 are positioned symmetrically on opposite sides of an entrance slot 28 provided in the base 12 and cover [3. Suitable bearing means 29 are provided for supporting each of the rollers 20 on its respective shaft. Shafts 24 and 21 may be constructed and supported in the manner illustrated for shaft 25 in Figure 14.. This shaft extends through a boss 30 on the base 12 and is secured by means of a threaded nut 3 I. A shoulder 32 on the shaft engages the upper end of the boss 30.

Means are provided for turning the ring [6, and as shown in the drawings this means includes a sprocket 33 secured to the ring [6 by means of a plurality of threaded elements 34. The sprocket 33 is provided with an entrance opening aligned with the opening l! in the ring [5. The sprocket 33 is driven by means of a chain 35 which is trained around idler sprockets 36 and 31 and driven from the driving sprocket 38. The sprockets 36 and 31 are carried by the upper portions-of the shafts 23 and 26. As

shown in Figure 12 the sprocket 36 is fixed on a hub 39 by means of weld metal 48. The hub 39 is rotatably mounted on an eccentric portion 4I of the shaft 23 by means of suitable bearing assemblies 42. The purpose of the eccentric portions 4| on the shafts 23 and 26 is to provide means of adjustment of the tension in the chain 35. In order to take up slack either or both of the shafts 23 and 26 may be turned. This is accomplished by unscrewing the nuts 43 and 44 and removing the cap screw 45. A ring 46 provided with a noncircular opening receives a noncircular portion 4'! on the shaft so that by turning the ring 46 the shaft may be turned to any desired angular position. The cap screw 45 is then reinserted into one of the holes 48 in the ring 46 in order to secure the shaft at the selected angular position. The nuts 43 and 44 are then retightened. Turning of the shaft 23 does not affect the position of .the roller 28 which is mounted on a concentric portion of the shaft.

It will be understood that the construction and mounting of the sprocket 31 on the shaft '26 is substantially identical to the construction and mounting of the shaft 23 shown in Figure 12.

The driving sprocket 36 is mounted on a squared portion 49 of the power shaft 59 so that the sprocket 38 rotates with the shaft. The shaft 59 is rotatably mounted in axially spaced bearings and 52 carried by the base I2 and auxiliary cover 53 respectively. The cover 53 is secured to the base I2 by means of a plurality of threaded elements 54. The cover 53 and base i2 cooperate to define a chamber 55, and within this chamber are mounted a pair of driving gears 56 and 51 and a pair of driven gears 58 and 59. The driving gears 56 and 51 are fixedon a driving shaft 60 by means of suitable keys 6|. The driven gear 59 is rotatably mounted on the power shaft 58, while the driven gear 53 is slidably mounted on a squared portion 62 of the shaft 50 so that it will slide axially of the shaft but must rotate therewith. Interengaging clutch faces 63 and 64 are provided on the gear 59 and gear 59 respectively.

Means are provided for shifting the gear 58 into engagement with the driving gear 56 and for simultaneously separating the interengaging jaw faces 63 and 64. As shown in Figures 3 and this means includes a yoke 65 having elements '66 engaging in the groove 61 and carried on a pivotally mounted yoke shaft 68. I The shaft 68 extends outwardly through the base I2 and is provided with a pair of actuating levers 69 on opposite sides of the tong device. Detent means 10 may be provided for releasably latching the levers 69 in either the upper or lower position.

Means are provided for rotating the shaft 60, and as shown in the drawings this means includes an air motor generally designated II. This air motor H may be of any conventional or desirable type and is preferably provided with an actuating lever 12 for reversing the direction of rotation. The motor II receives the upper end of the shaft 60 in driving relation. Air under pressure is supplied to the motor II by way of the piping 13 which also acts as a support for the outer end of the air motor I I.

A supply conduit 14 communicates with an air compressor reservoir or other suitable source of compressed air and also communicates with the air control valve i5 via fitting 16. The valve I5 is provided with a manually operable lever 11 which may be conveniently operated from either side of the tong device l6. The valve may be 'vided in the ring I6.

positioned directly below the location of the air motor II and overlies the arm I8 which extends from the base I2. An eye 19 is provided at the outer end of the arm I8 for attachment to a cable, as will be described hereinafter.

Actuation of the lever TI opens the air control valve 75 and causes the air motor 2I to rotate the shaft 69. The shaft 56 may be driven from the shaft 66 at a low speed through gears 57 and 59 or at a high speed through gears 56 and 58. The shifter handles 69 are employed to render either the high speed or low speed drive effective. Rotation of the shaft 58 causes the sprocket 38 to drive the chain 35 and hence to turn the ring I6. As the ring I6 rotates the side opening I1 comes under the links of the chain 35 and the chain spans the opening during a part of the revolution of the ring I6.

Means are provided on the ring I6 to grip a pipe 86, and as shown in the drawings this means includes a carrier 83 on which pipe gripping jaws 8! and 92are mounted. The carrier 83 is positioned co-axially of the ring I6 and rests on an annular shelf 84 provided on the ring I6. The arcuate shoulders 85 and 86 provided on the carrier 83 are received between the upper and lower arcuate rims 81 and 86 respectively which are provided on the ring I6. The arcuate length of the shoulders 85 and 86 is made less than the width of the side opening I? pro- The carrier 83 may be assembled into the ring by aligning two of the surfaces 85 and 86 with the side opening I1 and then tilting the carrier 83 with respect to the ring.

The carrier 83 is .free to turn within the ring I6, being guided by the arcuate Walls 89 and 96. The jaw 82 is fixed to the carrier 83 by means of a single attaching pin 92. This fixed jaw 82 may be provided with a pair of circumferentially spaced pipe gripping dies 93 and 94. These dies extend vertically on the fixed jaw 82 and may be removed upon withdrawal of the holding elements 95 which pass through ears 96 formed on the jaw 82. The pin 92 fixed on the carrier 83 provides a pivotal mounting for the inner end of the lever 98. This lever extends outwardly from the carrier 83 into a position between upstanding drive pins 99 and Hill which are circumferentially spaced and fixed on the integral ring I6. A roller I8I is mounted on the pin I99, and a block I92 is rotatably mounted on the pin 99.

The movable jaw 8| is pivotally connected to the lever 95 by means of the pivot pin I64, and this jaw carries a removable pipe gripping die I95. As clearly shown in Figure 8 the movable jaw BI is provided with a pair of vertically extending lugs I96, and these lugs are adapted to engage the end surfaces I0! provided on the carrier 83. The main portion of the jaw 8| between its point of pivotal connection with the lever 98 and the lugs I86 is positioned between the upper and lower arcuate plates I88 of the carrier 83.

A brake rim I69 extends upwardly from the carrier plate I68 and is adapted to be contacted by a stationary brake band Iii) secured to the cover I3 by means of the attaching pins III. Friction lining i I2 may be provided on the band III The function of the band H8 and rim I09 is to retard rotation of the carrier 83.

From the above description it will be understood that rotation of the ring I6 from the position shown in Figure 5 to the position shown in Figure 6 causes the movable jaw iii to move from its fully retracted position to an operative posi- 5 tion in which the die I05 contacts the pipe 80. Since the brake band H and brake rim I09 cooperate to resist rotary movement of the carrier 83, the clockwise rotation of the ring I6 causes the lever 98 to pivot about the pin 92 and hence cause the lugs I03 on the movable jaw 8| to move inwardly toward the pipe 30 along the surfaces I0! provided on the carrier 83. After the pipegripping die I engages the pipe 80 further and continued rotation of the ring I6 drags the carrier 83 around with the ring I6 against the relatively light resistance offered by the brake band H0.

The pipe-gripping dies 93, 94 and I05 are spaced circumferentially of the pipe 80 to provide a solid grip for the pipe. The dies may be spaced at 120, or as shown in the drawings the dies 93 and 94 may be spaced at 90 with the jaw I05 positioned at about 135 from each.

After a pipe joint has been screwed up it is necessary to withdraw the tong device from the pipe. Accordingly, the side opening II in the ring I3 must be aligned with the entrance opening 28 in the base I2. The threads of the pipe joint may become tightened to any random position, and accordingly 2. means must be provided for turning the ring IS in a reverse direction in order to bring about alignment of the side opening I! with the entrance opening 28. As shown in the drawings, this means includes the reversing lever I2 on the air motor I I. This means further includes a positioning valve generally designated H3 shown in detail in Figures and 16. This valve includes a stationary housing I I 4 fastened to the cover l3 by means of screw elements H5 and provided with a central bore H6. A central valve stem HI is fitted within the bore H6 and is provided with a central groove H8. The lower end of the stem III carries a roller H9 which is adapted to roll on the upper surface of the sprocket 33.

When the roller I9 encounters the cam I which is mounted on the sprocket 33 it raises the valve stem from the position shown in Figure 16 to the position shown in Figure 1'7. In this latter position the groove I I8 is out of alignment with the side ports I24 and I22 communicating with the pipes I23 and I24 respectively. These pipes are connected to .the air supply conduit I4 in a manner to bypass the air control valve I5. Thus the fitting It connects the pipe I24 with the air supply conduit I4 upstream from the ai control valve I5, while the fitting I26 connects the pipe I23 with the downstream side of the air control valve I5.

From this description it is to be understood that whenever the positioning valve H3 is in the open position as shown in Figure 16, air under pressure is sup-plied to drive the air motor II. Accordingly, the carrier 83 and pipe-gripping jaws BI and 82 may be driven in a counterclockwise direction by actuating the reverse lever I2 and by manually depressing the nob l2! on the upper end of the positioning valve stem I IT. This causes the air motor to rotate in a reverse direction and to rotate the sprocket 33 and ring I6 until the roller H9 rides up on the cam I20, shutting off the air supply to the air motor II. The cam I20 is positioned on the sprocket 33 in the proper angular position to bring the side opening ll of the ring IS into alignment with the entrance opening 28 in the base [-2 when the air motor H stops turning.

As shown in Figures 1, 3, 9 and 11a guard generally designated I28 may be pivotally mounted on the shaft 22. The upper end of the shaft may be threaded to receive a threaded bushing I29. A boss I30 on the upper portion I3I of the guard I28 is provided with a bore I35 to receive the ex ternal cylindrical surface of the bushing I29. The upper and lower portions I3l and I32 01' the guard I28 may be secured together by means of a bolt I33 connecting adjoining ears I34. A bore I36 in the lower portion I32 is positioned in alignment with the bore I35 and is adapted to receive a cylindrical projection I31 on the bushing I 38 which is threaded to the lower portion of the shaft 22-. A pair of vertically spaced ears I39 extends from the upper portion I3I of the guard I28 and is pivotally connected to one end of a spring housing I40 by means of the pivot pin MI. The housing I40 is slotted at one end as shown at I42 to receive a stationary pin I43 in sliding relation. The pin I43 is fixed on a pair of projections I44 provided on the cover I3. A compression spring I45 is mounted in the cylinder I40 and bears against the pivot pin I4I at one end and against the stationary pin I43 at the other end. The position of the pins I4I, I43 and the shaft 22 is such that an over-center mounting is provided for the guard I28. Thus the compression spring I45 is adapted to maintain the guard I28 in either the open position as shown in Figure 1 or the closed position as shown in Figures 3 and 4.

The upper portion I3I of the guard I28 comprises a substantially flat sheet adapted to overlie the cover I3. Similarly, the lower portion I32 of the guard includes a sheet adapted to underlie a portion of the base I=2. Each of the sheets is cut away to provide a substantially semicircular recess I46 and a finger I 41. When the tong device I0 is initially moved toward the pipe the finger I41 contacts the pipe and rotates the guard as the tong device I0 approaches the pipe 80. As the pipe 80 passes into the entrance slot 28 and into the side opening I! in the ring is the guard moves to the closed position, as indicated in Figure 3, and is maintained closed by the action of the spring I45. In its closed position the guard acts as a barrier protecting the operator of the tong from injury by any possible contact with the ring I3 or the teeth of the sprocket 33.

- Any suitable or desirable means may be provided for supporting the tong in operative position. As shown in Figures 1 and 2 a pair of brackets I48 may be provided on the cover I3 and base I2, and a connector pin I49 carried on each bracket I48 may be used to connect with such supporting device. A preferred form of supporting device is shown in my co-pending application for roll-over tong support filed of even date herewith.

In operation, the tong device I0 is moved toward the pipe 80 which engages the finger I4! on the guard I28 as it enters the slot 2 8 provided in the frame II. The pipe 80 passes through the side opening I I in the ring I 6, and movement of the tong device is arrested by contact of the pipe 80 with the dies carried in the stationary jaw 82. The guard I28, meanwhile, has taken the closed position illustrated in Figure 3. One of the shifter levers 69 is actuated by the operator to engage the high speed drive. The operator then opens the air control valve I3 by manipulation of the valve handle 11. This supplies air pressure to the fluid motor II and causes it to turn the shafts 60 and 59, thereby rotating the driving sprocket 38. The chain 35 then rotates the driven sprocket 33 in clockwise direction.

gage the low speed drive.

The brake band I It acts to restrain initial rotation of the carrier 83, and accordingly the lever 98 moves from the position shown in Figure to the position illustrated in Figure 6, thereby moving the jaw 8I from the retracted position to its operative position on the pipe 89. Continued rotation of the sprocket 33 and ring I6 rotates the carrier as a unit with the ring I6 against the relatively light resistance offered by the brake band III), thereby turning the pipe 80. A backup line 81 is fastened to the eye 19 as shown in Figure 1, to resist bodily swinging movement of the tong device under the reaction torque of the ring I6.

The screwing motion of the pipe continues until the threads tighten to the point Where the air motor II stalls under overload. The operator then moves one of the shifter handles 69 to en- The greater torque available at low speed then continues the rotation of the pipe 80 until the joint is made up. The operator then releases the handle H of the air control valve I5, shutting off the supply of air pressure to the air motor H. The operator then actuates the reversing lever 12 on the air motor II and depresses the nob I21 on the stem of the positioning valve H3. The valve H3 and conduits I23 and I24 provide a bypass around the main air controlvalve I5, and hence air pressure is again applied to the air motor I I.

The sprocket 33 and ring I6 are then driven in a counterclockwise direction, and the efiect of the brake band I In is initially to resist rotation of the carrier 83. Accordingly, the lever 98 is pivoted about the pin 92 from the position shown in Figure 6 to the position shown in Figure 5, thereby retracting the movable jaw 8| and its die I 05 away from the pipe 80. Counterclockwise rotation of the lever 98 about the pin 92 and hence counterclockwise rotation of the ring I6 relative to the carrier 83 is limited by engagement of the lever surface 98a with the surface of the jaw 82. When the roller II9 carried on the stem of the positioning valve I I 3 rides up on the block I20 carried on the sprocket 33, the bypass connection around the main air control valve I5 is interrupted, cutting off the supply of air to the air motor II. The motor then stops with the position of the side opening I! in the ring substantially aligned with the location of the entrance slot 28 in the frame II. The tong device Il) may be moved away from the pipe, the pipe passing outwardly through the aligned opening 11 and slot 28 and moving the pivoted guard I28 back to its open position as shown in Figure 1.

If the roller H9 carried on the stem of the positionin valve II3 should happen to be positioned directly over the block I20 on the sprocket 33 when the pipe joint reaches its fully made up position, the operator would not be able to depress the nob E2? to open the positioning valve H3. In this position the ring opening I! is aligned with the frame slot 28 but the movable jaw 8| is in pipe-gripping position, and hence the jaw must be released before the pipe can be withdrawn through the opening I! and slot 28. Accordingly, when the nob I27 cannot be depressed the operator actuates the reversing lever E2 on the air motor TI and the main air control valve IS in order to rotate the ring I6 for a part of a revolution in a counterclockwise direction. The nob I2'I is then depressed and the valve handle I? released. The motor II is then driven in a reverse direction by air supplied to the bypass 8 via conduits I23 and I2 5, and the ring I6 comes to rest with the opening I? substantially aligned with the slot 28, and with the movable jaw BI in its retracted position. The pipe 86 may then be withdrawn through the aligned slot and opening.

The tong device Il] may be used for different pipe sizes by merely changing the jaws BI and 82. This is readily accomplished upon removal of the single pivot pin 92. When it is desired to use the tong for unscrewing sections of pipe instead of for screwing them together the entire tong device In may be inverted. The roll-over hanger described in my co-pending application above referred to is particularly useful in this regard. Figure 18 shows another method of using the tong device for unscrewing, i. e., for rotating the pipe in a counterclockwise direction. The movable jaw and fixed jaw may be removed from the carrier 83 and reassembled as shown in Figure 18. This is accomplished by withdrawing the pivot pin 92, thereby disconnecting the fixed jaw 82 from the carrier 83. The fixed jaw 82 may be removed from the carrier 83, and the movable J'aw 8I together with the pivotally connected lever 93 may also be removed. The jaws are then inverted and reassembled as shown in Figur 18, with the lever 98 positioned between the roller IEII and the rotatable block I50 positioned on the pin I5I. The pin I5I is fixed on the ring I6. The carrier 33 is symmetrical about a plane passing through its rotary axis and through the axis of the pin 92. Accordingly, the lugs IE6 on the movable jaw 8i ride against the surfaces Iilla, on the carrier 83. Counterclockwise rotation of the ring I6 first engages the movable jaw with the pipe, and continued rotation causes the carrier 83 to revolve with the ring I6 against the frictional resistance offered by the brake band.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

1. In a, power tong, the combination of: a frame; an integral ring rotatably supported on the frame and adapted to encompass a pipe, the r ng having a side opening through which the pipe may pass; a carrier journaled within the ring and adapted for limited axial turning movement relative to the ring; a first pipe-gripping element fixed relative to the carrier and provided with a pair of circumferentially spaced pipe contacting dies; a second pipe gripping element mounted for movement relative to the carrier between an operative pipe-gripping position and an inoperative retracted position; a pipe contacting die on the second element; means including a member adjacent one of the first said dies and operatively interposed between the ring and the carrier and adapted to shift the second element from one position to the other upon relative turning movement of the rin and carrier; power means to rotate the ring; and brake means adapted to retard rotation of the carrier.

2. In a power tong, the combination of: a frame; an integral ring rotatably supported on the frame and adapted to encompass a pipe, a carrier journalled within the rin and adapted for limited axial turning movement relative to the ring; a radially immovable pipe-gripping element fixed relative to the carrier, the ring and carrier each having a side opening through which the pipe may pass; a radially movable pipe-gripping element mounted for movement relative to the carrier between an operative" pipe-gripping position and an inoperative retracted position; means including a member positioned radially opposite the opening in the carrier and operatively interposed between the ring and the carrier and adapted to shift the radially movable element from one position to the other upon relative turning movement of the ring and carrier; power means to rotate the ring; and brake means carried by the frame adapted to retard rotation of the carrier.

3. In a power tong, the combination of: a frame; an integral rin rotatably supported on the frame and adapted to encompass a pipe, the ring having a side opening through which the pipe may pass; a carrier mounted on the ring and adapted for limited axial turning movement relative to the ring; a radially immovable pipegripping element fixed relative to the carrier; a radially movable pipe-gripping element mounted for movement relative to the carrier between an operative pipe-gripping position and an inoperative retracted position; a lever positioned adjacent the radially immovable element and operatively connected to both the ring and the carrier; pivot means connectin the lever and the radially movable element whereby the lever may shift the radially movable element from one position to the other upon relative turning movement of the ring and carrier; and power means to rotate the ring.

4. In a power tong, the combination of: a frame; an integral ring rotatably supported on the frame and adapted to encompass a pipe, the ring having a side opening through which the pipe may pass to a central position within the ring; a carrier positioned within the ring and adapted for limited axial turning movement relative to the ring; a first pipe-gripping jaw fixed on the carrier; a second pipe-grippin jaw m'ovably mounted on the carrier for movement between an operative pipe-grippin position and an inoperative retracted position away from the pipe, the second jaw and carrier having cooperating surfaces for guiding the second jaw between said positions; a lever operatively connected to both the ring and the carrier; pivot means connecting the lever and the second jaw whereby the lever may shift the second jaw from one position to the other upon relative turning movement of the ring and carrier; and power means to rotate the ring.

5. In a power tong, the combination of: a rotatable jaw carrier; a first pipe-gripping jaw fixed on the carrier; a second pipe-gripping jaw mounted on the carrier for movement toward and away from a central pipe, the second jaw and carrier havin cooperating surfaces for guiding movement of the second jaw; a lever pivotally mounted on the carrier; pivot means connecting the lever and the second jaw whereby the lever may shift the position of the second jaw; and means for moving the lever relative to the carmen 6. In a power tong, the combination of a rotatable jaw carrier; a first pipe-gripping jaw fixed on the carrier; a second pipe-gripping jaw mounted on the carrier for movement toward and away from a central pipe, the second jaw and carrier having cooperating surfaces for guiding movement of the second jaw; a lever pivotally mounted on the carrier; pivot means connecting the lever and the second jaw whereby the lever may shift the position of the second jaw; brake means for retarding rotation of the carrier; and

10' means for moving the lever relative to the carmen 7. In a power tong, the combination of: a frame; an integral ring rotatably supported on the frame and adapted to encompass a pipe, the ring having a side opening through which the pipe may pass to a central position within the ring; a carrier positioned within the ring and adapted for limited axial turnin movement relative to the ring; a first pipe-gripping jaw fixed on the carrier; a second pipe-gripping jaw movably mounted on the carrier for movement between an operative pipe-gripping position and an inoperative retracted position away from the pipe, the second jaw and carrier having cooperating surfaces for guiding the second jaw between said positions; a pair of circumferentially spaced drive elements on the ring; a lever pivotally mounted on the carrier and extending between said elements; means connecting the lever and the second jaw whereby the lever may shift the second jaw from one position to the other; and power means to rotate the ring.

8. In a power tong, the combination of: a frame provided with a pipe entrance slot; an integral ring rotatably supported on the frame and having a side opening adapted for alignment with said entrance slot; releasable gripping means carried on the ring adapted to engage a pipe; means including a prime mover mounted on the tong adapted to rotate the ring in either direction; conduit means supplying motive fiuid for the prime mover includin a pair of flow controlling valves connected in parallel; and cooperating part carried on the ring and frame and connected to said valves adapted to close one of the valves when the side opening and entrance slot arein substantial alignment.

9. In a power tong, .the combination of: a frame provided with apipe entrance slot; an integral ring rotatably supported on the frame and having a side opening adapted for alignment with said entrance slot; releasable gripping means carried on the ring adapted to engage a pipe; means including a fiuid driven motor mounted on the tong and adapted to rotate the ring in either direction; means supplying fiuid pressure to operate said motor, said means including a valve; and an actuator carried on the ring and connected to said valve adapted to close the valve to stop the fluid motor when the side opening and entrance slot are in substantial alignment.

10. In a power tong, the combination of: a frame provided with a pipe entrance slot; an integral ring rotatably supported on the frame and having a side opening adapted for alignment with said entrance slot; releasable gripping means carried on the ring adapted :to engage a pipe; means including a fiuid driven motor mounted on the-tong and adapted to rotate the ring in either direction; means including a main control valve for admitting pressure fluid to 0perate said motor; a bypass conduit extending around said main control valve; a positioning valve in said bypass conduit; and means carried on the ring adapted to close the positioning valve to stop the fluid motor when the side opening and entrance slot are in substantial alignment.

11. In a power tong, the combination of: a frame provided with a pipe entry slot; an integral ring rotatably supponted on the frame and having a side opening adapted for alignment with said entrance slot; releasable gripping means carried on the ring adapted to engage a pipe; an air motor supported on the tong; power transmission connections whereby the air motor may rotate the ring; means including a main control valve for admitting air pressure to operate said air motor; a bypass conduit extending around said main control valve; a selectively operable positioning valve in said bypass conduit and mounted on said frame; and an actuator carried on the ring and adapted to close the positioning valve to stop the air motor when the side opening and entrance slot are in substantial alignment.

12. In a power tong, the combination of: a rotatable jaw carrier; first and second pipe-gripping jaws mounted on the carrier; a pin adapted to secure the first jaw to the carrier, the carrier being symmetrical with respect to a plane passing through the axis of the pin and the rotary axis of the carrier; a lever pivotally mounted on the pin, the second jaw being pivotally attached to the lever and being guided for movement on the carrier toward and away from a central pipe; power means for moving the lever relative to the carrier, whereby the jaws cooperate to turn the pipe in one direction, the jaws upon withdrawal of said pin being adapted for assembly on the carrier in interchanged position whereby they may cooperate to turn the pipe in the other direction.

13. In a power tong, the combination of a frame; an integral ring rotatably supported on the frame and adapted to encompass a pipe, the ring having a side opening through which the pipe may pass to a central position within the ring; a jaw carrier positioned within the ring and adapted for limited axial turning movement relative to the ring; a pipe gripping jaw assembly adapted to be mounted on the carrier in a first position to rotate the pipe in one direction or in a second position to rotate the pipe in the other direction; a single pivot pin adapted to secure the assembly to the carrier in either, position; a lever pivotally mounted on said pivot pin and adapted to cause the jaw assembly to grip the pipe; and means on the ring adapted to actuate the lever.

14. In a power tong, the combination of: a frame; an integral ring rotatably supported on the frame and adapted to encompass a pipe, the ring having a side opening through which the pipe may pass to a central position within the ring; a jaw carrier positioned within the ring and adapted for limited axial turning movement relative to the ring; a pipe gripping jaw assembly adapted to be mounted on the carrier in a first position to rotate the pipe in one direction or in a second position to rotate the pipe in the other direction, said assembly including a fixed jaw and a movable jaw; a pivot pin adapted to secure the fixed jaw to the carrier in either position of the assembly; a lever pivotally mounted on the pivot pin; pivotal means connecting the lever and the movable jaw; and means on the ring adapted to actuate the lever.

15. In a power tong, the combination of: a frame; an integral ring rotatably supported on the frame and adapted to encompass a pipe, the ring having a side opening through which the pipe may pass to a central position within the ring; a jaw carrier positioned within the ring and adapted for axial turning movement relative to the ring; releasable pipe gripping jaws mounted on the carrier; means responsive to relative tuming movement of the ring and carrier adapted to cause the jaws to grip the pipe; a driven sprocket fixed on the ring and adapted to rotate the ring; a brake rim on the carrier positioned radially within said sprocket and enclosed by the frame; and a brake band assembly fixed to the frame and engaging the rim to retard rotation of the carrier.

16. In a power tong, the combination of: a frame; an integral ring adapted to encompass a pipe and having a side opening through which the pipe may pass to a central position within the ring; releasable means mounted on the ring for gripping the pipe; means including a plurality of rollers for rotatably supporting the ring on the frame, at least one of said rollers being rotatably mounted on a shaft carried on the frame and extending parallel to the rotary axis of the ring, the shaft having an eccentric portion; an idler sprocket rotatably mounted on said eccentric portion; a driven sprocket fixed on the ring; power means including a chain trained over said sprockets adapted to drive the ring; and means whereby the shaft may be angularly oriented relative to the frame to shift the position of the idler sprocket without shifting the position of the roller.

1'7. In a power tong, the combination of: a frame; an integral ring rotatably supported on the frame; a carrier journaled on the ring co-axially thereof, the ring and carrier each having a side opening through which the pipe may pass to a co-axial position; a radially immovable pipegripping element fixed relative to the carrier; a radially movable pipe-gripping element mounted for movement relative to the carrier between an operative pipe-gripping position and an inoperative retracted position; a lever; a pivot pin on the carrier opposite the carrier opening connecting the lever to the carrier; a second pivot pin connecting the movable pipe-gripping element to the lever; and drive means on the integral ring engaging the lever.

18. In a power tong, the combination of: a frame; an integral ring rotatably supported on the frame; a carrier journaled on the ring coaxially thereof, the ring and carrier each having a side opening through which the pipe may pass to a co-axial position, the carrier opening being wider than the ring opening; a radially immovable pipe-gripping element fixed relative to the carrier; a radially movable pipe-gripping element mounted for movement relative to the carrier between an operative pipe-gripping position and an inoperative retracted position; a lever; a pivot pin on the carrier opposite the carrier opening connecting the lever to the carrier; a second pivot pin connecting the movable pipe-gripping element to the lever; and drive means on the integral ring engaging the lever.

CHESTER A. LUNDEEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,300,995 Moody Apr. 15, 1919 1,417,490 Brandon May 30, 1922 1,478,020 Butler Dec. 18, 1923 1,505,007 Cox et al Aug. 12, 1924 1,660,853 Wilson Feb. 28, 1928 1,955,727 Adams Apr. 24, 1934 2,000,221 Dawson May 7, 1935 2,305,624 Lange et al. Dec. 22, 1942 2,317,306 Smith Apr. 20, 1943 2,405,757 Rowland Aug. 13, 1946 

